High 7.5Published Oct 8, 2026

CVE-2026-107300msgpack5: Many buffered values can exhaust the streaming decoder stack

Updated under an hour ago (2026-10-19 07:30 UTC)

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It affects mcollina msgpack5. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.43%, higher than 35% of scored CVEs.

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Every CVE for mcollina msgpack5

Exploited in the last 30 days

msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder recursively invokes itself for each complete MessagePack value remaining in a chunk. A remote peer can send one chunk containing many small valid values, causing recursion proportional to the value count, exhausting the JavaScript call stack, and interrupting the process or stream. This issue is fixed in version 6.1.0.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-674
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.43% (percentile 35)
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 8, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

mcollina msgpack5 mcollina:msgpack5 (from the name)	before 6.1.0	CNA record

References

https://github.com/mcollina/msgpack5/security/advisories/GHSA-5x5g-h9x8-2fh9x-refsource-confirm
https://github.com/mcollina/msgpack5/commit/77fbef144d05def5d16fc22c37caa64c0a7efebax-refsource-misc
https://github.com/mcollina/msgpack5/releases/tag/v6.1.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.